PT-2026-56011 · Traefik · Traefik

Matte1782 · Published 2026-07-06 · Updated 2026-07-06 · CVE-2026-54763

Mitre

CVSS v4.0

7.8

High

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

Traefik is an HTTP reverse proxy and load balancer. Prior to v2.11.51, v3.6.22, and v3.7.6, Traefik's BasicAuth, DigestAuth, and ForwardAuth middlewares strip canonical-cased spoofed identity headers before writing Traefik's own value, but do not account for underscore-variant header names, which many backends normalize identically to dashed forms. An attacker able to reach a protected route can inject an underscore-variant header that survives Traefik's stripping and reaches the backend alongside, or on the unauthenticated ForwardAuth authResponseHeaders path instead of, the value Traefik intended to set, spoofing identity or authorization context. This issue is fixed in versions v2.11.51, v3.6.22, and v3.7.6.

Fix

Insufficient Verification of Data Authenticity

Authentication Bypass by Spoofing

Weakness Enumeration

CWE-178

CWE-345

CWE-290

Related Identifiers

CVE-2026-54763

Affected Products

Traefik

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-54763 · Security Note
• https://github.com/traefik/traefik/commit/108a5264473a2cbc8f12d6d691a3c6553cdf2c1b · Note
• https://github.com/traefik/traefik/security/advisories/GHSA-x677-9fxg-v5c5 · Note
• https://github.com/traefik/traefik/pull/13262 · Note